The Cretaceous/Paleogene boundary in the Neuquén basin, northern Patagonia, Argentina

PARRAS, ANA; CASADIO, SILVIO; NAÑEZ, CAROLINA; CONCHEYRO, ANDREA; GRIFFIN, MIGUEL

San Luis

Otro; 10 Reunión Argentina de Sedimentología; 2004

Asociación Argentina de Sedimentología

During the Maastrichtian-Danian interval, southern South America was amply covered by the Atlantic Ocean. The land area was then reduced to an archipelago in which the central part of the Somun Curá Massif and the Deseado Massif were the main emergent zones. The large surface covered by the sea then was an important paleogeographic feature and played a crucial role in climatic and evolutionary processes, as it was – for some groups –a biogeographic barrier between Patagonia and the rest of South America (Pascual, 1998; Casadío, 1999). Towards the West, the Andean volcanic arc became an important feature interrupting the Atlantic-Pacific connection and also the major sediment source for the adjoining basins. Sedimentary rocks recording these geodynamic events in the Neuquén Basin are included in the Malargüe Group, and are well exposed in southern Mendoza, northeastern Neuquén, western La Pampa and northern Río Negro. The rocks involved were studied by numerous workers in the final part of the nineteenth and early part of the twentieth centuries. During the last decade, a renewed interest on them has surfaced because they contain the Cretaceous/Paleogene boundary, in both marine and continental facies. Therefore, they become an excellent opportunity to learn about…